Empirical relations for the evaluation of resonant frequency and quality factor of the TM010 mode of circular substrate integrated waveguide (SIW) resonators

In this paper, empirical relations for the evaluation of both the resonant frequency fr and the quality factor Q for the dominant TM010 mode of a circular substrate integrated waveguide (SIW) cavity resonator are proposed and validated. These formulas are based on well established analytical expressions valid for the case of circular metallic cavity resonator, in which an equivalent radius Req, empirically derived, is employed. Their effectiveness is demonstrated by comparing the empirical predictions with the full wave results.